Xmonad

xmonad is a dynamic window manager (tiling) for the X Window System, noted for being written in the functional programming language Haskell. Begun in March 2007, version 0.1 was announced in April 2007 as 500 lines of Haskell. xmonad is a tiling window manager—akin to dwm, larswm, and StumpWM. It arranges windows in a non-overlapping pattern, and enables managing windows without using the mouse. xmonad is packaged and distributed on a wide range of Unix-like operating systems, such as a large number of Linux distributions, and Berkeley Software Distribution (BSD) systems. While originally a clone of dwm (derivative in areas such as default keybindings), xmonad now supports features not available to dwm users such as per-workspace layout, tiling reflection, state preservation, layout mirroring, GNOME support and per-screen status bars; it can be customised by modifying an external configuration file and 'reloaded' while running. xmonad features have begun to influence other tiling window managers: dwm has borrowed "urgency hooks" from xmonad, has also included Xinerama support (for multihead displays) with release 4.8, and patches exist to reimplement xmonad's Fibonacci layout. Haskell In 2007 the man page stated: By utilising the expressivity of a modern functional language with a rich static type system, xmonad provides a complete, featureful window manager in less than 500 lines of code, with an emphasis on correctness and robustness. Internal properties of the window manager are checked using a combination of static guarantees provided by the type system, and type-based automated testing. A benefit of this is that the code is simple to understand, and easy to modify. Extensions to the core system, including emulation of other window managers, and unusual layout algorithms, such as window tiling based on the Fibonacci spiral—have been implemented by the active community and are available as a library.